Audio Speakers

• Speakers are the most common output devices used with computers system.
• It converts a electrical audio signal into a corresponding sound.
• Speakers are contain a speaker enclosure or speaker cabinet which is often a rectangular or square box made of wood or sometimes plastic.
• The enclosure play an important role in the quality of sound.
• Where high fidelity reproduction of sound is required, multiple loudspeakers transducers are often mounted in the same enclosure, each reproducing a port of the audible frequency range.
• In this case the individual speakers are referred as loudspeaker.

Types of speakers or drivers

Full range drivers

• A full range driver is a speaker designed to be used alone to reproduce an audio channel without the help of other drivers, and therefore must cover the entire audio frequency range.
• These drivers are used in small radios, intercoms, public address system etc.

Woofer

• It reproduces low frequencies.
• These drivers works with the characteristics of the enclosure to produce suitable low frequencies.

Subwoofer

• A subwoofer is a woofer driver used only for the lowest pitched part of the audio frequencies.
• Below 200 Hz for consumers system, below 100 Hz for professionals and below 80 Hz in THX approved systems.

Mid-range drivers

• It is a loudspeaker driver that reproduces a band of frequencies generally between 1-6 kHz.

Tweeter

• A tweeter is a high-frequency driver that reproduces the highest frequencies in a speaker system.

Coaxial drivers

• A coaxial driver is a speaker driver with two or several combined concentric drivers.

How speakers works?

• At the front of a loudspeaker, there is a fabric, plastic, paper, or lightweight metal cone which is called diaphragm.
• The outer part of the cone is fastened to the outer part of the loudspeaker's circular metal rim.
• The inner part is fixed to an iron coil (voice coil), that sits just in front of a permanent magnet.
• When you hook up the loudspeaker to a stereo, electrical signals feed through the speaker cables into the coil.





• This turns the coil into a temporary magnet or electromagnet.
• As the electricity flows back and forth in the cables, the electromagnet either attracts or repels the permanent magnet.
• This moves the coil back and forward, pulling and pushing the loudspeaker cone. The moving cone pumps sounds out into the air.

My notes